Ubuntu 20.04 LTS USN-4671-1 Critical: Firefox Denial of Service

ubuntu

December 15, 2020

Firefox could be made to crash or run programs as your login if it opened a malicious website.

Summary

Firefox could be made to crash or run programs as your login if it

opened a malicious website.

Software Description:

- firefox: Mozilla Open Source web browser

Details:

Multiple security issues were discovered in Firefox. If a user were

tricked into opening a specially crafted website, an attacker could

potentially exploit these to cause a denial of service, obtain sensitive

information, bypass the CSS sanitizer, bypass security restrictions,

spoof the URL bar, or execute arbitrary code. (CVE-2020-16042,

CVE-2020-26971, CVE-2020-26972, CVE-2020-26793, CVE-2020-26974,

CVE-2020-26976, CVE-2020-26978, CVE-2020-26979,

CVE-2020-35113, CVE-2020-35114)

It was discovered that the proxy.onRequest API did not catch

view-source URLs. If a user were tricked in to installing an

extension with the proxy permission and opening View Source, an

attacker could potentially exploit this to obtain sensitive

information. (CVE-2020-35111)

Topics Covered

security advisory denial of service software update threat attack firefox ubuntu

Update Instructions

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.10:
  firefox                         84.0+build3-0ubuntu0.20.10.1

Ubuntu 20.04 LTS:
  firefox                         84.0+build3-0ubuntu0.20.04.1

Ubuntu 18.04 LTS:
  firefox                         84.0+build3-0ubuntu0.18.04.1

Ubuntu 16.04 LTS:
  firefox                         84.0+build3-0ubuntu0.16.04.1

After a standard system update you need to restart Firefox to make
all the necessary changes.